1. Field of the Invention
The present invention relates to a bending tube for endoscope (i.e. curved pipe for endoscopes) that performs a bending movement according to an operation of an operation section.
2. Description of the Related Art
An endoscope with which an image of an object in a body cavity is displayed on a screen of a display device by inserting an elongated insertion section into the body cavity has been conventionally used widely. For example, in a flexible endoscope the insertion section of which has flexibility, among endoscopes of that kind, the insertion section is configured such that a distal end rigid portion, a bending section and a flexible tube section are provided in a coupled manner in that order from the distal end side.
The bending section is configured to be bendable, for example, in two directions of up and down directions, two directions of right and left directions, or four directions of up, down, right and left directions associated with the object image displayed on the display device. In order to enable such a bending movement, the bending section is generally configured being provided with a bending tube (a set of bending sections) with multiple joint pieces rotatably coupled via rotation pins. An angle wire is inserted in the bending tube, and a bending movement of the bending section is performed by pulling or releasing the angle wire.
Recently, a bending tube using superelastic alloy material is proposed as a bending tube simply configured without using joint pieces and rotation pins. This kind of bending tube is configured by providing multiple slots on a cylindrical pipe material (a bending tube body) using laser processing or the like, for example, as disclosed in Japanese Patent Application Laid-Open Publication No. 9-288239. Furthermore, in order to simplify the configuration of the bending tube more, a technique of integrally forming a wire supporter (a wire guide) for inserting an angle wire by deforming a part of a ring-shaped part of the pipe material in an inner diameter direction of the pipe material is disclosed in Japanese Patent Application Laid-Open Publication No. 9-288239.